docs: add signature especially for the api docs

Author: ST-DDT

src/random.ts

@@ -179,6 +179,26 @@ export class Random {
     object: T,
     field?: unknown
   ): T[K];
+  /**
+   * Returns a random key or value from given object.
+   *
+   * @template T The type of `Record` to pick from.
+   * @template K The keys of `T`.
+   * @param object The object to get the keys or values from.
+   * @param field If this is set to `'key'`, this method will a return a random key of the given instance.
+   * If this is set to `'value'`, this method will a return a random value of the given instance.
+   * Defaults to `'value'`.
+   *
+   * @example
+   * const object = { keyA: 'valueA', keyB: 42 };
+   * faker.random.objectElement(object) // 42
+   * faker.random.objectElement(object, 'key') // 'keyB'
+   * faker.random.objectElement(object, 'value') // 'valueA'
+   */
+  objectElement<T extends Record<string, unknown>, K extends keyof T>(
+    object: T,
+    field?: 'key' | 'value'
+  ): K | T[K];
   objectElement<T extends Record<string, unknown>, K extends keyof T>(
     object = { foo: 'bar', too: 'car' } as unknown as T,
     field = 'value'